1996 Saturn SC1 milky residue in coolant tank

I have a 96 saturn sc1 that ran hot and the head cracked,so i replaced the head with a good used one,replaced the head gasket,I flushed the coolant a couple of times to get the pure milk out,but I can't seem to get all of it,there is some residue in the coolant tank that is mixed with coolant. Any suggestions? Should I worry or just drive the car? By the way i have driven the car about a 150 miles since repairs and it has not ran hot at all. Please reply? Thanks jjevans79